The present invention relates to a power-and-free conveyor.
Power-and-free conveyors are already well known which comprise a power line, a free line coextensive with the power line thereabove, a multiplicity of pivotally movable pushers adapted to travel with a drive chain for the power line, engaging dogs mounted on carrier free trolleys on the free line, and anticoasting dogs mounted on the free trolleys and each opposed to the engaging dog. These conveyors are used for automating flow production. With the conveyor line system, carriers are switched for joining or diversion from one line to another article processing line, or the pushers propelling carriers are changed over to other pushers. A carrier stopping device or the like which is separate from the power-and-free conveyor is conventionally used in such a case for joining or diverting carriers or for changing pushers. The system therefore has the problem of requiring a very high equipment cost and a wide space.
Accordingly, it has recently been desired to provide a power-and-free conveyor in which pushers can be changed over or carriers can be joined together or diverted without necessitating any special device other than the conveyor.
The conventional conveyor has another problem. Since the engaging dog and the anticoasting dog are fixed to the free trolley, the engagement of the pusher with the engaging dog exerts great impact on the free trolley and consequently to the carrier, causing trouble to the work on the article in transit, such as a motor vehicle assembly, and further producing noises.